1、

#include <stdio.h>

#define swap(type, a, b)  {type tmp = a; a = b; b = tmp;}

int main(void)
{
    int x = 5, y = 10;
    printf("initial value   x = %d\n", x);
    printf("initial value   y = %d\n\n\n", y);
    
    swap(int, x, y);
    
    printf("processed value x = %d\n", x);
    printf("processed value y = %d\n", y);
    
    return 0;
}